1. Field of the Invention
The present invention relates to depilatories and in particular, to a depilatory utilizing water soluble adhesive blend which eliminates the need for removal of waxy residue by a solvent or the like.
2. Description of the Prior Art
Depilatories are well known in the art and have been used for many years, particularly by women, to remove body hair. Initially, a depilatory consisted of waxes blended with tackifying resins, simply termed “wax”, which was melted and applied to the skin and allowed to set. It was stripped from the skin and in doing so, removed unwanted hair. This type of treatment can be obtained in a beauty salon or performed at home. “Waxes” utilized in a depilatory treatment were petroleum based waxes and resins typically rosin based. As such, after having stripped or removed, there remained on the skin a waxy, resinous residue. Since the composition inherently contained water insoluble ingredients, this residue also was not water soluble, and had to be removed from the skin with a suitable solvent such as baby oil or mineral oil which then necessitated rinsing the skin with water and soap or detergent.
Depilatories in sheet like form or strips have also been developed wherein the petroleum based wax/resin mixture is precoated on a substrate. The individual would purchase a package of such depilatories, the sheets containing the “wax” would then be applied to the skin and allowed to set and then stripped away and removed. This procedure suffers from the same problem as described previously where the “wax” is applied from a container directly to the skin. A waxy, resinous residue remains once the wax has been peeled away and this residue must be removed with an appropriate solvent such as baby oil or mineral oil which also necessitates rinsing with water and soap or detergent.
Sugar based “waxes” have been developed which can be applied to the skin from a container for the removal of body hair. These “waxes” are water soluble and therefore do not require a solvent for the removal of any residue, the residue being removable with water. However, the sugar based waxes are not suitable on sheets or strips for application in that they lack a sufficient viscosity, and lack sufficient thermal stability. Other water soluble waxes have been developed, but they too have not been compatible or suitable to coating onto a substrate for use in a sheet or strip type depilatory.
Applicant has developed a sheet or strip type depilatory utilizing a water soluble adhesive blend and the process for making same that allows for suitable shelf life for the product. The product can be maintained and not deteriorate over a wide temperature range and still performs the hair removal function. The ability to provide the user or individual with a sheet or strip depilatory with a water soluble adhesive blend allows the user to apply the depilatory for the removal of hair and subsequently remove the depilatory and wash away or shower away the residue which remains. The individual no longer is required to remove a residue with a suitable solvent such as baby oil or mineral oil and to then wash away or take a shower to remove the solvent. It also provides the individual with the convenience of a water soluble sheet or strip depilatory heretofore unavailable with sugar based “waxes”.
Water solubility or dispersability of the hot melt adhesive is accomplished by the incorporation of appropriate hydrophilic raw materials which individually or in combination with other selected components, including surfactants, emulsifiers, waxes, resins, plasticizers and polymers provide the desired functionality.
Examples of water soluble or water dispersable polymers comprise polyvinyl alcohol (PVOH), polyvinyl pyrrolidone (PVP), vinyl pyrrolidone, vinyl acetate (PVP/VA), polyethyl-oxazoline (PEOX), branched sulfo-polyesters (Eastman AQ Branched Polyesters), manufactured by Eastman, and polyvinyl methyl ether.
Suitable waxes can include those such as ethoxylated montan wax (Hoechst wax KST), polyethylene glycol waxes, and ethoxylated alcohols (Unithox) manufactured by Baker Hughes.
Desirable plasticizers incorporated to improve water solubility and dispersibility and lower viscosity are liquid polyethylene glycols, polyethylene aryl ethers and monomeric plasticizers such as diethylene glycol dibenzoate (Benzoflex 2-45), dipropylene glycol dibenzoate (Benzoate 9-88), both manufactured by Velsicol Chemical Corp. Solid plasticizers such as dicyclohexyl phthalate and 1-4 cyclohexane dimethanol may be added to enhance, tack and raise the melting point of the adhesive to prevent cold flow under elevated temperature conditions. Surfactants and emulsifying agents are numerous and well known in the industry. Of those that we have discovered to be particularly useful are nonylphenol ethoxylated polyethylene glycol (Igepal 880) manufactured by Rhone-Poulenc and dioctyl ester of sodium sulfo-succinic acid (Aerosol OT-100) by Cytec.
Resins are employed to enhance tack and adhesion. Suitable resins that can be blended into the adhesive are rosins, disproportionated rosin soaps, hydroabietyl alcohol, polymerized rosin, rosin derivative and rosin derived dimeric acids.